Similar to conductive polymers, conductive oligomers are used as conductive materials for various electronic devices. Aromatic compounds comprising aromatic rings with .pi. electrons, which are freely movable in a molecule, or one-dimensional conjugate macromolecules bonded by double bonding--such as polyacetylene--are typical examples of these conductive organic materials. The orientation of molecules or molecular chains is one of the important factors influencing the conductivity (mobility of electrons or holes) of the conductive materials.
Conventional methods of orienting compounds include the following:
natural orientation due to an interaction among molecules or molecular chains that is characteristic of the compounds; PA1 selectively orienting the compounds in the process of forming a conductive polymer by providing a fine groove on a substrate surface and filling the groove with a reaction catalyst (Japanese Published Patent Application No. Hei 3-21861); PA1 orienting a conductive polymer by fixing both ends of a wet conductive polymer during the process of forming the conductive polymer through electrolytic polymerization, and PA1 gradually drying and processing the polymer with heat, thus orienting the polymer due to its shrinkage (Japanese Published Patent Application No. Hei 2-44607); and PA1 orienting a conductive polymer by fixing both ends of the polymer and mechanically drawing the polymer. PA1 The orientation of a conductive oligomer is generally created by natural orientation due to, an interaction among substituents of the molecules or van der Waals force. PA1 recognizing the usefulness of the molecular arrangement technique employing the PTFE oriented film; PA1 providing a high orientation property to large areas of conductive materials and to thin films of the materials; and PA1 increasing the mobility of conduction electrons.
However, it has been difficult for the above-noted conventional technologies to orient large areas of conductive materials or thin films of these materials. When a conductive material is applied to an electronic device, conduction carriers (electrons or holes) should have high mobility without being trapped. However, no good method has been found for orienting oligothiophene as a conductive material.
A molecular arrangement technique employing a polytetrafluoroethylene (PTFE) oriented film has been used mainly for polymer materials, and its usefulness has been realized. However, the usefulness of the above-mentioned technique for orienting materials which have rigid molecular structures and comparatively low molecular weights, such as conductive oligomers, has not been established.